Bacterial Hand Contamination and Transfer after Use of Contaminated Bulk-Soap-Refillable Dispensers

Abstract

Bulk-soap-refillable dispensers are prone to extrinsic bacterial contamination, and recent studies demonstrated that approximately one in four dispensers in public restrooms are contaminated. The purpose of this study was to quantify bacterial hand contamination and transfer after use of contaminated soap under controlled laboratory and in-use conditions in a community setting. Under laboratory conditions using liquid soap experimentally contaminated with 7.51 log 10 CFU/ml of Serratia marcescens, an average of 5.28 log 10 CFU remained on each hand after washing, and 2.23 log 10 CFU was transferred to an agar surface. In an elementary-school-based field study, Gram-negative bacteria on the hands of students and staff increased by 1.42 log 10 CFU per hand (26-fold) after washing with soap from contaminated bulk-soap-refillable dispensers. In contrast, washing with soap from dispensers with sealed refills significantly reduced bacteria on hands by 0.30 log 10 CFU per hand (2-fold). Additionally, the mean number of Gram-negative bacteria transferred to surfaces after washing with soap from dispensers with sealed-soap refills (0.06 log 10 CFU) was significantly lower than the mean number after washing with contaminated bulk-soap-refillable dispensers (0.74 log 10 CFU; P < 0.01). Finally, significantly higher levels of Gram-negative bacteria were recovered from students (2.82 log 10 CFU per hand) than were recovered from staff (2.22 log 10 CFU per hand) after washing with contaminated bulk soap (P < 0.01). These results demonstrate that washing with contaminated soap from bulk-soaprefillable dispensers can increase the number of opportunistic pathogens on the hands and may play a role in the transmission of bacteria in public settings.

Händehygiene in Einrichtungen des Gesundheitswesens

“…7 KbE/ml kontaminiert [261,262]. Das Nachfüllen wird auch in weiteren Studien als Kontaminationsursache verbunden mit Ausbrüchen angesehen [260,[263][264][265][266]. Auch nosokomiale S. marcescens Infektionen waren mit der Kontamination eines flüssigen Handwaschpräparats assoziiert [25,267].…”

“…Waschen mit einem kontaminierten flüs-sigen Handwaschpräparat die Anzahl Gram-negativer Erreger auf den Händen ansteigt und eine Weiterverbreitung auch in Gemeinschaftseinrichtungen möglich erscheint [263]. …”

Compendium of Veterinary Standard Precautions for Zoonotic Disease Prevention in Veterinary Personnel: National Association of State Public Health Veterinarians: Veterinary Infection Control Committee 2015

“…82,84,86 Hand soaps may be susceptible to bacterial overgrowth and have been associated with nosocomial infections. 87 To prevent creation of a bacterial reservoir or cross-contamination, no additional soap should be added to liquid soap dispensers before they are empty (ie, they should not be topped off); once completely empty, refillable dispensers should be cleaned and dried, then refilled with liquid soap or sealed soap refills. 82 Water temperature has little effect on the removal of microorganisms from hands, but warm (as opposed to cold) water improves compliance.…”

Fluorescence Assay for Evaluating Microbicidal Activity of Hand Antiseptics

“…A known limitation of the EN1500 standard is that the efficacy of disinfectants is determined only against E. coli (11,23). Although the purpose of the rule is to compare various disinfectants under this norm, the effectiveness of disinfectants could be tested against other microorganisms of interest according to the EN1500 method and the fluorescent method by using fluorogenic assays suitable to other microorganisms (13,24).…”